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When it comes to saving America's endangered species, science -- not politics -- ought to be the driving force.

We've seen what happens when Congress steps in. In 2011, for the first time ever, politicians abruptly decided that wolves in five states should immediately lose their Endangered Species Act protection. Since then, more than 1,100 wolves have been killed.

Unfortunately, some politicians in D.C. seem emboldened by what they did to wolves and now want to insert themselves into other decisions about which species do and don't get federal protection -- decisions that in the past have been rightly driven by knowledgeable scientists and the law.

The latest episode is in Washington state, where U.S. Rep. Doc Hastings (R-WA 4th District) is complaining about protection for two highly endangered plants, the pretty White Bluffs bladderpod and Umtanum desert buckwheat. Endangered Species Act protections were finalized in April after years of review. Now, after Hastings complained, the U.S. Fish and Wildlife Service is delaying those protections for six months.

Last year, there was a similar delay of protections for the dunes sagebrush lizard in Texas and New Mexico after politicians there stepped in. Ultimately, the Fish and Wildlife capitulated to those complaints and completely cancelled protections for the lizard -- even though its own scientists said those protections were needed to prevent extinction.

These are certainly not the first incidents of political meddling by members of Congress in decisions that are required by law to be based solely on the best science. But they are of serious concern, not only because they are placing plants and animals at increased risk of extinction, but because the Fish and Wildlife Service is in the process of working its way through a backlog of species known to need protection stretching back decades, and doing so with an increasingly pinched budget.

In the case of the two Washington plants, none of the facts support a need to delay protection.

Perched atop Columbia River bluffs that, until the 1970s, had remained largely intact since the Pleistocene Epoch, the two plants face many threats, including off-road vehicles, invasive species and landslides caused by underground seepage from excess irrigation water.

The plants were first identified by the agency's scientists as in need of protection way back in 1999, but rather than being granted such protection, they were placed on a candidate list along with hundreds of other species, some that had been there since the 1970s.

Here's why delays matter: At least 24 species that we know of have gone extinct waiting for protection, including the Amak Song Sparrow and Tacoma pocket gopher.

The clock is always ticking for species living on the edge of extinction. The Endangered Species Act has a rigorous thoughtful process for deciding which plants and animals should get protected. When the Act is allowed to do its job, it's amazingly successful: 99 percent of the species under its care have been spared extinction (think: grizzly bears, gray whales and bald eagles) and hundreds are on the road to recovery.

That success comes about because the Act requires a science-driven process that typically leads to protection of an endangered species' most important habitat and a detailed plan for its recovery.

But that process doesn't work when politicians play scientists and purport to know how best to manage wildlife on behalf of the American people. It's not what was intended when President Nixon signed the Endangered Species Act 40 years ago and isn't what's best for the plants and animals that are relying on it for their survival.